Clinical use of the co-formulation of insulin degludec and insulin aspart.

AIMS: To provide a review of the available data and practical use of insulin degludec with insulin aspart (IDegAsp). Premixed insulins provide basal and prandial glucose control; however, they have an intermediate-acting prandial insulin component and do not provide as effective basal coverage as true long-acting insulins, owing to the physicochemical incompatibility of their individual components, coupled with the inflexibility of adjustment. The molecular structure of the co-formulation of IDegAsp, a novel insulin preparation, allows these two molecules to coexist without affecting their individual pharmacodynamic profiles. METHODS: Clinical evidence in phase 2/3 trials of IDegAsp efficacy and safety in type 1 and type 2 diabetes mellitus (T1DM and T2DM) have been assessed and summarised. RESULTS: In people with T2DM, once- and twice-daily dosing provides similar overall glycaemic control (HbA1c ) to current modern insulins, but with lower risk of nocturnal hypoglycaemia. In prior insulin users, glycaemic control was achieved with lower or equal insulin doses vs. other basal+meal-time or premix insulin regimens. In insulin-naïve patients with T2DM, IDegAsp can be started once or twice-daily, based on individual need. People switching from more than once-daily basal or premix insulin therapy can be converted unit-to-unit to once-daily IDegAsp, although this strategy should be assessed by the physician on an individual basis. CONCLUSIONS: IDegAsp offers physicians and people with T2DM a simpler insulin regimen than other available basal-bolus or premix-based insulin regimens, with stable daytime basal coverage, a lower rate of hypoglycaemia and some flexibility in injection timing compared with premix insulins.

Relationship of thyroid hormone levels and cardiovascular events in patients with type 2 diabetes.

Alterations in thyroid hormone levels are found associated with inflammation in patients with non-thyroidal illness (NTIS) and are common in patients with type 2 diabetes mellitus (T2DM). Inflammation has also been linked with development of cardiovascular events (CVE) in T2DM. Our objective was to assess whether thyroid hormone abnormalities typical of NTIS in patients with T2DM are related to inflammation and CVE. This was a cross-sectional study of 140 subjects; 70 with T2DM and 70 as a control group paired by age, sex and body mass index (BMI). We recorded age, sex, BMI, waist/hip ratio, diabetes duration, HbA1c, CVE history, serum amyloid A (SAA), TSH, total (T) and free (F) T4 and T3, reverse T3 (rT3) and TT3/rT3 ratio. Patients with T2DM had lower levels of TT4 (p = 0.012), TT3 (p < 0.001), FT3 (p < 0.001) and TT3/rT3 (p = 0.002). They also showed higher FT4 (p < 0.001) and similar TSH levels (p = 0.627) compared to the control group. SAA levels correlated positively with rT3 (r = 0.45; p < 0.001) and inversely with TT3/rT3 (r = -0.38; p = 0.001). Patients with T2DM and history of CVE had higher rT3 (p = 0.006) and lower TT3/rT3 (p = 0.002), along with higher SAA levels (p = 0.002) than patients without this characteristic. Multiple logistic regression showed that factors independently associated with CVE were older age (OR = 1.159, 95 % CI 1.011-1.329), male sex (OR = 4.391, 95 % CI 1.081-17.829) and higher TT3/rT3 (OR = 0.993, 95 % CI 0.987-0.999). We have confirmed the presence of NTIS in T2DM. We also showed that thyroid hormone abnormalities are associated to inflammatory activity and to CVE in these patients.

Rosiglitazone decreases intra- to extramyocellular fat ratio in obese non-diabetic adults with metabolic syndrome.

BACKGROUND: Insulin resistance is intrinsically related to intramyocellular (IMCL) rather than extramyocellular (EMCL) triglyceride content. Conflicting results have been reported on the ability of insulin sensitizer agents, such as thiazolidinediones, to modify muscle fat distribution. The aim of this study was to investigate the role of rosiglitazone on muscle fat compartment distribution in an adult population of obese non-diabetic metabolic syndrome patients. PATIENTS AND METHODS: Fifteen obese, non-diabetic, metabolic syndrome patients were studied by means of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy before and after treatment with rosiglitazone 8 mg/day for 6 months. Anthropometrical and metabolic variables were assessed. RESULTS: After rosiglitazone, body weight and hip circumference increased [100.9 (91.12-138.7) vs. 107.0 (79.6-142.8) kg and 118 (107-126) vs. 122 (110-131) cm]; while waist-hip ratio (WHR) decreased from 0.93 (0.87-1.00) to 0.89 (0.82-0.97) (P < 0.001 for all). Additionally, fasting plasma glucose, insulin and homeostatis model assessment of insulin resistance (HOMA-IR) significantly decreased while adiponectin increased over threefold [9.7 (3.7-17.7) vs. 38.0 (19.3-42.4) microg/ml] without any changes in resistin. Finally, the IMCL did not change [267.54 (213.94-297.94) vs. 305.75 (230.80-424.75) arbitrary units (AU), P = 0.15] while the EMCL increased [275.53 (210.39-436.66) vs. 411.39 (279.92-556.59) AU; P < 0.01] therefore decreasing the IMCL-to-EMCL (IMCL/EMCL) ratio [1.07 (0.78-1.23) vs. 0.71 (0.53-0.96); P < 0.01]. CONCLUSION: Rosiglitazone treatment increased body weight and hip circumference and decreased WHR. More importantly, it decreased the IMCL/EMCL ratio by increasing the EMCL without any significant change on the IMCL.

Adiponectin is related to intramyocellular lipid content in non-diabetic adults.

OBJECTIVE: Insulin resistance (IR) is associated with intramyocellular lipid (IMCL) content and low serum adiponectin (ADP) levels and ADP is also involved in muscle fat oxidation. However, the relationship between ADP and IMCL content is still controversial and in this study we explored it further in non-diabetic adults. DESIGN: Cross-sectional clinical study. SUBJECTS: Thirty-three adult subjects, 24 obese non-diabetic patients with metabolic syndrome (MS) and 9 lean healthy controls. MEASUREMENTS: Proton nuclear magnetic resonance spectroscopy (1H-NMRS) was performed to quantify IMCL content. The latter plus serum ADP, anthropometrics and biochemical parameters were evaluated and compared in these 2 groups. RESULTS: MS patients had higher body mass index, waist, waist-to- hip ratio, glucose, insulin, and triglycerides and lower HDL cholesterol (HDLc) compared to controls. Homeostasis model assessment of IR (HOMA-IR) [3.25 (2.58-4.13) vs 1.02 (0.73- 1.29); p<0.0001] and IMCL content [266.1 (189.9-296.3) vs 72.85 (55.3-109.4) AU, p<0.0001] were higher, and quantitative insulin-sensitivity check index (QUICKI) [0.32 (0.31-0.33) vs 0.38 (0.37-0.40); p<0.0001] and ADP [8.6 (4.05-15.95) vs 21.1 (12.9- 24.4) microg/ml; p=0.02] were lower in MS subjects compared to controls. IMCL content was directly associated to glucose, insulin, triglycerides, and HOMA-IR and inversely to HDLc, QUICKI and, more importantly, to ADP (r=-0.41; p<0.05). Only in the MS group, ADP partially influenced IMCL content. CONCLUSION: ADP is inversely related to IMCL content in non-diabetic adults. This finding has possible implications for the role of ADP in muscle fat oxidation, IR, and MS.

Atherogenic lipid profile of Brazilian near-term newborns.

Cardiovascular disease is the primary cause of death in Brazil. Recent studies have shown that low birth weight and preterm birth are linked to a higher prevalence of cardiovascular disease. The aim of the present study was to compare the levels of lipids and apolipoproteins and atherogenic indexes between term and near-term newborn infants. A sample of umbilical cord blood was obtained from 135 newborns (66 males) divided into two groups: 25 near-term neonates (35-36.6 weeks of gestational age) and 110 term neonates (37-42 weeks of gestational age). The total cholesterol concentrations were higher in the near-term neonates than in the term group (94.04 +/- 8.02 vs 70.42 +/- 1.63 mg/dl, P < 0.01), due to an increase in the LDL-cholesterol fraction in the near-term group (57.76 +/- 6.39 vs 34.38 +/- 1.29 mg/dl, P < 0.001). The atherogenic indexes (total cholesterol/HDL-cholesterol, LDL-cholesterol/HDL-cholesterol and apolipoprotein B/apolipoprotein A-I) were higher in the near-term group (P < 0.001, P < 0.001, and P < 0.05, respectively). The gestational age of the newborns was inversely correlated with total cholesterol and LDL-cholesterol, and also with the total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol indexes. These findings demonstrate that the lipid profile is worse in the group of near-term neonates compared with the term group. Future studies are needed to determine if this atherogenic profile in near-term neonates can affect body metabolism, increasing the risk for cardiovascular diseases in adult life.

Atherogenic lipid profile of Brazilian near-term newborns

Cardiovascular disease is the primary cause of death in Brazil. Recent studies have shown that low birth weight and preterm birth are linked to a higher prevalence of cardiovascular disease. The aim of the present study was to compare the levels of lipids and apolipoproteins and atherogenic indexes between term and near-term newborn infants. A sample of umbilical cord blood was obtained from 135 newborns (66 males) divided into two groups: 25 near-term neonates (35-36.6 weeks of gestational age) and 110 term neonates (37-42 weeks of gestational age). The total cholesterol concentrations were higher in the near-term neonates than in the term group (94.04 ± 8.02 vs 70.42 ± 1.63 mg/dl, P < 0.01), due to an increase in the LDL-cholesterol fraction in the near-term group (57.76 ± 6.39 vs 34.38 ± 1.29 mg/dl, P < 0.001). The atherogenic indexes (total cholesterol/HDL-cholesterol, LDL-cholesterol/HDL-cholesterol and apolipoprotein B/apolipoprotein A-I) were higher in the near-term group (P < 0.001, P < 0.001, and P < 0.05, respectively). The gestational age of the newborns was inversely correlated with total cholesterol and LDL-cholesterol, and also with the total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol indexes. These findings demonstrate that the lipid profile is worse in the group of near-term neonates compared with the term group. Future studies are needed to determine if this atherogenic profile in near-term neonates can affect body metabolism, increasing the risk for cardiovascular diseases in adult life.

99mTc-sestamibi thyroid uptake in euthyroid individuals and in patients with autoimmune thyroid disease.

PURPOSE: We investigated the biokinetics of (99m)Tc-sestamibi in the thyroid of euthyroid volunteers (EVs) and in patients with autoimmune thyroid diseases and determined the best time interval between (99m)Tc-sestamibi injection and calculation of uptake. METHODS: Forty EVs, 30 patients with Graves' disease (GD), 15 patients with atrophic Hashimoto's thyroiditis (AHT) and 15 patients with hypertrophic Hashimoto's thyroiditis (HHT) underwent (99m)Tc-sestamibi thyroid scintigraphy. Dynamic images were acquired for 20 min, and static images were obtained 20 min, 60 min and 120 min post injection. Five-, 20-, 60- and 120-min uptake, time to maximal uptake (T(max)) and T(1/2) of tracer clearance were calculated. Thyroid hormones and antibodies were measured. (99m)Tc-pertechnetate uptake was investigated in GD patients. RESULTS: T(max) was approximately 5 min in all four groups. The mean T(1/2) value for EVs was similar to the GD value and lower than the HHT and AHT values. The mean (+/-SD) 5-min uptake was 0.13% (+/-0.05%) for EVs. The 5-min uptake in GD was higher than that in EVs(P<0.001) and correlated with free thyroxine (r=0.54) and with (99m)Tc-pertechnetate uptake (r=0.68). Uptake in HHT was higher than that in AHT (P=0.0003) and EVs (P=0.002). Uptake in AHT was lower than uptake in EVs (P=0.0001). CONCLUSION: Five minutes is the optimal time interval between (99m)Tc-sestamibi injection and calculation of thyroid uptake. Five-minute uptake differentiates euthyroid individuals from GD patients. There is a high correlation between (99m)Tc-sestamibi and (99m)Tc-pertechnetate uptake in GD. The reduced (99m)Tc-sestamibi uptake in AHT patients is probably due to glandular destruction and fibrosis. Inflammatory infiltrate and high mitochondrial density in thyrocytes possibly explain the increased uptake in GD and HHT.

Inverse relationship between cord blood adiponectin concentrations and the number of cigarettes smoked during pregnancy.

BACKGROUND: Maternal smoking is linked with several neonatal metabolic disorders. Adiponectin is an adipose-specific hormone with anti-inflammatory and antiatherogenic properties. AIM: The aim of this study was to evaluate the effect of maternal smoking on cord blood adiponectin concentrations. METHODS: We evaluate the effect of maternal smoking on cord blood adiponectin concentrations comparing 14 full-term and seven preterm newborns born to mothers who smoked during pregnancy with 77 full-term and 10 preterm neonates born to non-smokers mothers. RESULTS: Maternal smoking during pregnancy was significantly associated with decreased adiponectin levels of preterm newborns (p < 0.05). CONCLUSIONS: Our findings also reveal a significant relationship between the reported number of cigarettes smoked during pregnancy and cord blood adiponectin concentrations (p = 0.01), suggesting that this association could have a causal relationship.

HLA-DRB1*04 and HLA-DQB1*03 association with the atrophic but not with the goitrous form of chronic autoimmune thyroiditis in a Brazilian population.

Autoimmune chronic lymphocytic thyroiditis appears in two forms, goitrous and atrophic. The evidence available is not enough to prove that the goitrous precedes the atrophic form, but immunogenetic analysis suggests that they may be distinct entities. The distribution of HLA class II alleles DRB1* and DQB1* was verified in patients from the region of Campinas, São Paulo, Brazil with both forms of thyroiditis. Ninety-one patients with primary hypothyroidism through autoimmune thyroiditis were classified as goitrous - 54 patients, 42.27 +/- 11.72 years old, having had hypothyroidism for 8.57 +/- 6.63 years - or atrophic - 37 patients, 42.72 +/- 12.01 years old, hypothyroidism for 6.73 +/- 4.07 years. The distribution of class II alleles was determined, DRB1* and DQB1* were genotyped after purifying DNA blood samples using the DNAzol technique, and the low-resolution PCR-SSP system was utilized for determination of generic alleles. Chi-square and Fisher's exact test were utilized to compare the distribution frequency of HLA alleles and the significant p-values were subjected to Bonferroni correction. We have demonstrated that the DRB1*04 allele is associated with autoimmune thyroiditis, and that there are genotypic differences regarding the presentation forms with a strong association between DRB1*04 and DQB1*03 and the atrophic form only.

Does maternal smoking influence leptin levels in term, appropriate-for-gestational-age newborns?

OBJECTIVES: Leptin, a hormone produced in adipose tissue and the placenta, is correlated with neonatal growth. The aim of this study was to investigate the effect of maternal smoking during pregnancy on cord blood leptin concentrations in term, appropriate-for-gestational-age infants. METHODS: Two groups of term, appropriate-for-gestational-age newborns were selected: 19 infants of smoking mothers and 91 infants of non-smoking mothers. Neonatal anthropometric measurements were taken and leptin levels were measured by radioimmunoassay. RESULTS: Leptin concentrations were similar (p=0.915) between the groups. Leptin levels correlated only with ponderal index (p < 0.01) and gestational age of the newborns (p < 0.05). CONCLUSIONS: This study indicates that maternal smoking during pregnancy does not affect cord blood leptin levels in term, appropriate-for-gestational-age infants.

Sibutramine enhances insulin sensitivity ameliorating metabolic parameters in a double-blind, randomized, placebo-controlled trial.

AIM: To assess the effect of sibutramine-assisted weight reduction program on insulin sensitivity and metabolic parameters in obese normal glucose tolerant individuals over a period of 24 weeks. RESEARCH DESIGN AND METHODS: A double-blind, placebo-controlled, parallel, prospective clinical trial was carried out at our medical centre. Forty female normal glucose tolerant patients, body mass index: 34.3 +/- 2.9 kg/m2 and age: 41.1 +/- 9.9 (range: 19-58 years), were randomized to placebo or sibutramine, 10 mg once daily. RESULTS: Seventeen patients from sibutramine group and 14 placebo had completed the study protocol. Significant weight change was seen in sibutramine (p < 0.01) (-5.6 kg or -6.1% vs. +0.9 kg or +1.1% in placebo). Insulin sensitivity enhanced in sibutramine group (Kitt: from 4.03 +/- 1.97 to 5.09 +/- 2.48%/min; p < 0.05). Homeostasis model assessment-IR (HOMA-IR) decreased from 7.8 +/- 6.9 to 5.6 +/- 4.5 (p < 0.05). HOMA-beta also decreased from 508 +/- 381 to 374 +/- 256 (p < 0.05). No changes were observed in the placebo control group regarding insulin sensitivity or secretion. Concomitant reductions were observed in the sibutramine group in lipid parameters (triglycerides and high-density lipoprotein-cholesterol), uric acid and gamma-glutamyl transferase (p < 0.05). CONCLUSIONS: Sibutramine has demonstrated efficacy in reducing weight in non-diabetic women along with amelioration in insulin sensitivity and additional improvement in metabolic parameters.

The insulin tolerance test in morbidly obese patients undergoing bariatric surgery.

OBJECTIVE: To assess the effect of massive weight loss in relation to insulin resistance and its correlation to changes in glycemic homeostasis and lipid profile in severely obese patients. RESEARCH METHODS AND PROCEDURES: A prospective clinical intervention study was carried out with 31 morbidly obese women (body mass index: 54.2 +/- 8.8 kg/m(2)) divided into three groups according to their glucose tolerance test: 14 normal, 8 impaired glucose tolerance, and 9 type 2 diabetes. All subjects underwent an insulin tolerance test with intravenous bolus of 0.1 U insulin/kg body weight before silastic ring vertical gastroplasty Roux-en-Y gastric bypass surgery, and again at 2, 4, 6, and 12 months postoperatively. Fasting plasma glucose, hemoglobin A1c, and lipid profile were also evaluated. RESULTS: A reduction of 68 +/- 15% in initial excess body weight was evident within 1 year. Along with weight loss, the following statistically significant changes were found: an increase in the insulin-sensitivity index (Kitt) and a decrease in fasting plasma glucose and hemoglobin A1c, most notably in the type 2 diabetes group. An overall improvement in lipid profile was observed in all three groups. DISCUSSION: Bariatric surgery was an effective therapeutic approach for these obese patients because it reduced both weight and insulin resistance, along with improving metabolic parameters. Significant correlations were found between insulin resistance and metabolic improvements. Weight loss after bariatric surgery induced an improvement in metabolic fitness, related to the reduction in insulin resistance over a range of glucose tolerance statuses from normal to diabetic.

Antithyroid drugs inhibit in vivo HLA-DR expression in thyroid follicular cells in Graves' disease.

Antithyroid drugs have been reported to reduce the expression of HLA-DR in thyrocytes in Graves' disease, but only circumstantial evidence has been provided about their in vivo immunologic effects. This present study was designed to examine the in vivo immunologic effect of antithyroid drugs on thyroid follicular cells. The study was conducted on 25 patients who had Graves' disease in remission or in activity and who were or were not receiving treatment (7 in overt thyrotoxicosis, 6 patients in remission, and 12 patients under medication). HLA-DR expression in thyroid biopsies was verified by immunohistochemistry. The follicular cells of all patients in overt thyrotoxicosis expressed HLA-DR whereas those of patients in remission were negative for HLA-DR. HLA-DR was also not expressed in all patients under medication, but this did not correlate with the clinical evolution after thyroid drug withdrawal. In conclusion, antithyroid drugs inhibit follicular cell HLA-DR expression in Graves' disease, when thyrotoxicosis is controlled. This suggests that additional mechanisms not involving HLA-DR play a role in thyroid autoimmune disease.

Expression of the sodium iodide symporter and thyroglobulin genes are reduced in papillary thyroid cancer.

Altered expression of the gene encoding the sodium iodine symporter (NIS) may be an important factor that leads to the reduced iodine accumulation characteristic of most benign and malignant thyroid nodules. Both up- and down-regulation of NIS gene expression have been reported in thyroid cancer using several different methods. The goal of the present study was to accurately identify alterations in NIS gene expression in benign and malignant thyroid nodules using an accurate real-time quantitative RT-PCR assay system. Total RNA was prepared from 18 benign thyroid nodules, 20 papillary thyroid cancers, and 23 normal thyroid samples from 38 subjects. Quantitative RT-PCR was used to measure NIS and thyroglobulin (TG) mRNA expression in normal thyroid tissue and in each nodular tissue sample. Papillary thyroid cancer samples had significantly lower NIS mRNA expression (72 +/- 41 picogram equivalents [pg Eq]), than did benign nodules (829 +/- 385 pg Eq), or normal tissues (1907 +/- 868 pg Eq, P = 0.04). Most important, in the paired samples, NIS gene expression was decreased in each papillary thyroid cancer compared with normal tissue (69% median decrease; range, 40-96%; P = .013). Eleven of the 12 benign nodules also demonstrated lower NIS gene expression than the normal tissue (49% decrease; range, 2-96%; P = .04). Analysis of the paired samples demonstrated that Tg mRNA expression was significantly lower in each of the thyroid cancer samples than in corresponding normal tissue (759 +/- 245 pg Eq vs. 1854 +/- 542 pg Eq, P = .03). We have demonstrated a significant decrement in NIS gene expression in all papillary thyroid cancers and in over 90% of benign nodules examined compared with adjacent normal thyroid tissue, using a highly accurate quantitative RT-PCR technique. Similarly, thyroid cancers demonstrated significantly lower TG mRNA expression than corresponding normal thyroid. Reduced NIS expression may be an important factor in the impairment of iodine-concentrating ability of neoplastic thyroid tissues.

Serum leptin levels after bariatric surgery across a range of glucose tolerance from normal to diabetes.

BACKGROUND: A longitudinal, clinical intervention study with bariatric surgery was done to investigate the relationship between leptin levels, BMI, and insulin during weight loss across a range of glucose tolerance from normal to diabetes. METHODS: 43 morbidly obese patients (BMI: 42-75 kg/m2) undergoing vertical banded gastroplasty Roux-en-Y gastric bypass (VBG-RGB), were divided into 3 groups: 21 normal (NGT), 12 impaired glucose tolerance (IGT) and 10 type 2 diabetes (DM). Leptin, insulin, glucose, lipids and uric acid were measured at baseline and 2, 4, 6, and 12 months following surgery. RESULTS: BMI fell from 54.1 +/- 9.1 to 34.6 +/- 6.3 kg/m2, similarly in all groups. Leptin decreased from 73.9 +/- 8.7 to 16.9 +/- 10.2 ng/ml and was strongly correlated with BMI during 1-year follow-up (r = 0.78; p < 0.001). Linear univariate analysis for repeated evaluation showed a positive correlation between leptin and glucose, triglycerides, uric acid, and insulin. Multivariate regression analysis indicated that BMI was independently correlated with the decrease in leptin (p < 0.001), accounting for 66% of the variance in leptin levels during weight loss. These results were found in the NGT and IGT groups. In the DM group, a small additional influence in leptin levels was attributed to glucose decrease. CONCLUSIONS: A strong link between leptin and BMI was found after surgery. BMI was the main determinant of the decrease of leptin. In these patients submitted to bariatric surgery, ranging from normal glucose tolerance to diabetes, changes in insulin levels and metabolic parameters, except for glucose in the DM group, did not appear to be correlated with changes in leptin levels.

Thyroid suppression test with L-thyroxine and [99mTc] pertechnetate.

OBJECTIVE: The thyroid suppression test is still used in some centres as an adjunt in the diagnosis of autonomous functioning thyroid nodules. With the purpose of minimizing the disadvantages of the original T3 suppression test, we have evaluated the efficacy of a method using L-thyroxine as TSH suppression agent and [99 mTc] pertechnetate as radiopharmaceutical. DESIGN: Open nonrandomized prospective study MATERIALS AND METHODS: A control group of 15 normal volunteers (11 males, 4 females; 21-35 years, mean 26.4 years) and a patient group of 20 patients (18 females, 2 males; 27-83 years, mean 53.6 years) divided into 4 subgroups, were studied: 7 patients with autonomous functioning nontoxic nodules, 3 with autonomous functioning toxic nodules, 7 with Graves disease and 3 with nonautoimmune diffuse toxic goitre. Baseline thyroid uptake and imaging were begun 20 minutes after an intravenous injection of 370 MBq (10 mCi) of [99 mTc] pertechnetate. This was followed by a single daily intake of 2 microg/kg of L-thyroxine, for 10 days. Thyroid imaging and uptake were then repeated. RESULTS: In the control group [99 mTc] pertechnetate uptake after L-thyroxine suppression had a mean reduction of 75.8 +/- 7.69% (58-87%) in comparison to the baseline level. All subjects were euthyroid by clinical and laboratory criteria and none complained of side-effects, despite significant suppression of TSH levels. In the patient group, thyroid uptake after suppression decreased in 10 patients (maximum reduction 39%), was unchanged in 2 patients and increased in the remaining 8 patients. CONCLUSION: The method described was efficient for demonstration of autonomous thyroid tissue, since none of the patients showed significant reduction of thyroid uptake after L-thyroxine suppression compared with the control group. This test was as effective as the original T3 suppression test, but more convenient to the patient: no side-effects, ease of hormonal intake, low dosimetry and short stay in the nuclear medicine laboratory.

A novel mutation in the TPO gene in goitrous hypothyroid patients with iodide organification defect.

OBJECTIVE: To screen and subsequently sequence the TPO gene for mutations in patients with congenital goitre, hypothyroidism and evidence for an organification defect (positive perchlorate discharge test). PATIENTS: We have studied seven hypothyroid and congenitally goitrous patients from three unrelated families. DESIGN AND MEASUREMENTS: We have measured serum thyroid hormone levels, 131I uptake, serum TSH and serum Tg concentrations. Denaturing gradient gel electrophoresis (DGGE) of PCR amplified genomic DNA was used to screen for mutations in the TPO gene. RESULTS: DGGE identified the presence of two frameshift mutations: a GGCC duplication in exon 8 (homozygous in one family and heterozygous in the other family) and a heterozygous insertion of a single nucleotide (C) at position 2505-2511 in exon 14. In addition, we have detected an alteration in exon 11, not yet described in the literature, derived from a single nucleotide substitution of a C to G at position 2008, altering the well-conserved amino acid domain among the peroxidases superfamily. This mutation in exon 11 was present in two families that showed heterozygous mutation for exon 8 or for exon 14. CONCLUSIONS: These results could support the hypothesis for a putative compound heterozygosity pattern in the affected patients. The altered phenotype (goitre and hypothyroidism since birth) seems justifiable in view of the possible inactivating character of this novel mutation in exon 11.